Exhaust silencer



Feb. 27, MU ER 2,191,619

EXHAUST S ILENCER Filed June 9, 1934 wow L Q Q'OQ E; QC/D Patented Feb. 27, 1940 PATENT OFFICE EXHAUST BILENCEE Lloyd E. Muller, Flint, Mich, assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Application June 9, 1934, Serial No. 729,741

16 Claim.

This invention relates to silencers of the resonator type in which there are incorporated two or more telescopically related, radially spaced tubular elements and resides in a silencer of the mentioned type in which one of the tubular elements is so formed that a portion of it directly engages a next adjacent tubular element and in conjunction therewith provides a passage which communicates with the space betweer the tubular elements.

For a better understanding of the nature and objects of this invention, reference is made to the following specification wherein there are described the embodiments of the invention which are illustrated in the accompanying drawing.

In the accompanying drawing:

The two parts of Figure 1 constitute a longitudinal section through a silencer of the resonator type in which my invention is embodied.

Fig. 2 is a section taken on the line 2-2 of Figure 1.

, Figure 3 is a fragmentary longitudinal section through a silencer of modified form.

Figure 4 is a section taken on the line 4--4 of Figure 3.

The silencer which is shown in the drawing consists of an imperforate tubular shell ill in whose ends there are secured heads II and I2, through which extend centrally disposed openings which are surrounded by outwardly extending collars l5 and It in which the ends of an unobstructed tube l1 snugly flt. Throughout its circumference and length, except for a short portion adjacent the head H and a portion of considerable length adjacent the head I2, the tube I1 is pierced by a multitude of perforations i3 and is surrounded and snugly embraced by a tube I! which is pierced throughout its circumference and length by a multitude of smaller, more closely spaced perforations 20.

The annular space between the shell ill, the tubular element ll-l3 and the heads II and i2 is subdivided longitudinally by an imperforate stepped annular partition 2| and the annular space between the shell l0, the tubular element ll-ll, the head II and the partition 2i is divided into resonance chambers 22 and 23 by an imperforate annular partition 24,

The portion of the tube I3 to the right of the partition 2| in the drawing is surrounded by a tubular element 23 which is radially spaced from it and the shell l0. One end of the tubular element 2! fits snugly around the intermediate tubular portion of the partition 2i and is supported thereby. The other end of the tubular element 2| is constricted so -that there are pm vided therein circumferentially spaced portions 23 which engage and conform to the tube It and therebetween channels 42. The portions 23 may go be welded or otherwise secured to the tube II or may be left free to slide thereon upon differential expansion of the tubular element 25 and the tube ID.

The tubular element 23 subdivides the annular space between the partition 2|, the head I2, the shell l0 and the tubular element i1--l9 into an inner annular space and an outer annular space. The inner annular space is divided by imperforate annular partitions 21 and 28 into resonance chambers 23, 30 and 3|. The outer annular space is divided by imperforate annular partitions 32 and 33 and an annular partition 34 through which extend tubes 35 into resonance chambers 36, 31, 33 and 39. The resonance chambers 38 and 31 communicate with the resonance chambers 29 and 30, respectively, through openings 40 and 4| in the tubular element 25;

The resonance chamber 39 communicates with the resonance chamber 38 through the tubes 35 in the partition 34 and with the resonance chamber 3! through the channels 42 between the portions 26 of the constricted end of the tubular e1ement 2!.

The simple resonators 20- I 8-42 and 20l 323 and the compound resonators 20-4 8--29-40--36, 20-l3--30-4l-31 and 20I8--3l42-39-38 are so proportioned and dimensioned, in the manner set forth in the Wilson applications Serial Numbers 470,'700 and 633,265 and the corresponding foreign patents, viz., Canadian Patents Nos. 348,037 and 353,352, British Patents Nos. 391,180 and 417,935, French Patents Nos. 720,611 and 754,580 and Italian Patents Nos. 300,037 and 324,615, that when the silencer which is shown in the drawing is installed in the ezdaamt system of the automotive vehicle for which it was-designedwlth the exhaust pipe of the propelling engine connected to the collar II and the tail pipe of the system connected to the collar I! the resonators will respond to and attenuate the sound waves which occur in the exhaust of the engine. g

It is clear that by constricting the right end of the tubular element 25 in the manner shown in the drawing, I provide, without resorting to the use of a third element, means for supporting that end of the tubular element 25 from the tubular element l1l8 without interrupting communication between the resonance chambers 3| and 33. The expedient under consideration is particularly useful in the construction of silencers of the resonator type since the acoustical conductivity of the channels 42 can be varied by changing their number, shape and/or length.

Many applications and variations of the expedient under consideration in the next preceding paragraph will suggest themselves to those skilled in the art. Figures 3 and 4 of the drawing show fragmentarily a modified form of the silencer illustrated in the preceding figures in so which the expedient has been applied so as to eliminate the necessity 01' providing the pertition 8 This is accomplished by constricting the shell id and expanding the tubular element so that there are provided therein portions, 66 and ti, which mutually engage and conform to each other and therebetween channels and 53 which communicate with the resonance chembers t8 and 39. Obviously, the chsnnels 52 or the channels 53 may be omitted or the deprescient; 52 and 53 may be so disposed that eecli of the depressions 52 conjointly with one of the depressions 53 constitutes a single channel,

It will be apparent from a consideration of figures 3 and i that the expedient under considerution msy beupplied when one desires to support an end of a, tubular element from s tubular element which surrounds it rather than from one which it surrounds by expanding instead of constricting the end of the first-mentioned tubular element and that the construction illustrated Figures 1 and 2 or the construction suggested in this paragraph may be modified by providing the channels in the supporting instesd of the supported element or in both the supporting and the supported elements.

It will also be apparent from a consideration of Figures 3 and 4.- thet the construction illuse trated in Figures 3. and 2 or the constructions suggested in the next preceding paragrspb. may be modified by expanding or constricting the supporting element instead or or in addition to constricting or expanding the supported element and from a consideration of Figures 1 and 2 that the construction illustrated in Figures 3 and may be modified by expanding more the tubular element and eliminating the constriction in the shell W or constricting more the shell it and eliminating the expansion in the tubular element '5 claim:

3.. in a silencer, two telescopically related, rsdially spaced tubular elements which constitute walls of s chamber, apassege of which. the chamber constitutes a side brunch extending through the inner of the tubular elements-one of the tubular elements being deformed tronsversely throughout 2. portion only of its length so as to change its diameter throughout its circumference and bring it into contact with. the other throughout 'a, portion. only of its circum fereucein order to provide means for supporting one of the tubular elements from the other and a passage which communicates with the chamber.

2. In a, silencer, two telescopically related, ra

dially spaced tubular elements which constitute walls of a chamber, a passage of which. the chamber constitutes a. side branch extending through the inner of the tubular elementsthe outer of the tubular elements being corrugated longitudinally throughout 8. portiononly of its length so that its external diameter reduced and the inwardly directed corrugations contact with the inner of the tubular elements at points distributed around its circumference in order to provide 7 means for supporting one of the tubular elements from the other and passages which communicate with the chamber.

'3. In a. silencer, two telescopically related, radially spaced tubular elements which constitute walls of a chamber, a. passage or which the cham ber constitutes a side branch extending through the inner of the tubular elements-one end of the outer or the tubular elements being deformed inwcrdly so es to change its diameter throughout its circumference and bring it into contact with the inner of the tubular elements throughout 2. portion only of its circumference in order to pro vide means for supporting one or the tubular elements from the other and a passage which communicates with the chamber.

4'4. In a. silencer, two telescopically related rs dially spaced tubular elements which constitute wells of a chamber, a passage of which the chamber constitutes a side branch extending through the inner of the tubular elements, a tubular ele merit of which a portion is surrounded by the outer oi the first specified tubular elements end which surrounds a portion only of the inner oi tions contact with the inner of the first specified tubular elements at points distributed around .its circumference in order to provide means for supporting the third specified tubular element from the inner of the first specified tubular ele ments and passages which communicate with the space between the inner of the first and the third specified tubular elements and the space between the first specified tubular elements beyond the end of the third specified tubular element.

5. In a silencer, two telescopically related, rsdi== oily spaced tubular elements which constitute walls of a chamber, a passage of which the chem ber constitutes a side branch extending through the inner oi the tubular elements-one oi the tubular elements being deformed transversely throughout a. portion only of its length so as to provide in it longitudinally extending furrows end change its diameter throughout its circumierence to bring it into contact with the other throughout a portion only of its circumference in order to provide support for one of the tubular elements from the other and a passage which communicates with the chamber.

6. A muiller having an inner shell provided with e plurality of relatively small perforations and having an imperiorate portion, an outer imperiorate shell having its ends closed, an intermediate shell, said inner and intermediate shells =forming between them an inner chamber and said intermediate and outer shells forming between theman outer chamber, an end of said intermedi-- ate shell being provided with longitudinally and inwardly disposed grooves extending into engagement with said inner shell about said imperforate portion of said inner shell, the portions of said 3 intermediate shell between said grooves forming restricted passages between said inner and inter" intermediate and outer shells forming between them an outer chamber, a. portion of said intermediate shell extendlngabout said imperforate portion of said inner shell being providedwlth 75 longitudinal grooves extending into engagement with said inner shell to form between said grooves passages connecting said inner and outer chambers, said passages being of greater'length than breadth and forming with said outer chamber a neck type resonator.

8. A muiiier comprising an inner shell through which gases and sound waves may pass from end to end, an intermediate shell arranged about said inner shell, said inner shell having an opening through which sound waves may pass into a space between said inner and intermediate shells, means for closing one end of said space, said intermediate shell having longitudinally extending portions thereof extending into contact with said inner shell and forming channels between said portions, and an outer shell having its ends closed and extending about said intermediate shell and forming therewith a resonance chamber, said channels connecting said space and said resonance chamber.

9. A mufiler having an inner shell provided with a plurality of relatively small perforations and having an imperforate portion, an outer imperforate shell having its ends closed, an intermediate shell, said inner and intermediate shells forming between them an inner chamber and said intermediate and outer shells forming between them an outer chamber, said inner chamber receiving gases and sound waves from said inner shell through said perforations, and a passage connecting said inner and outer chambers and of less cross-sectional area than said inner chamher and of materially greater length than width and formed partly by said imperforate portion of the inner shell, for conducting gases and sound waves from said inner chamber to said outer chamber.

10. A muffler having an inner shell provided with a plurality of relatively small perforations, an outer imperforate shell having its ends closed,

an intermediate shell, said inner and intermediate shells forming between them an inner chamber and said intermediate and outer shells forming between them an outer chamber, and connecting v passages between said inner and outer chambers through which gases and sound waves may travel in a direction lengthwise of the muiiler, said passages being of greater length than their width in a radial direction and of lesser cross-sectional area than the cross-sectional area of said inner chamber and being formed by longitudinal ridgesformed on at least one of the shells forming said passages.

11. A muiiler comprising an inner perforate shell forming a passage for gases through the muflier, an outer shell and an intermediate shell surrounding said inner shell and arranged in spaced relation to said inner shell and to each other, heads closing the ends of said outer shell and having openings communicating with said inner shell, bailles forming inner chambers between said inner and intermediate shells and into which sound waves pass through the perforations of said inner shell, and elongated channels of greater length than transverse dimensions between said inner and intermediate shells for conducting sound waves from said inner shell to the space between said outer and intermediate shells.

12. A muflier including an inner shell through which gases and sound waves pass, an outer shell and an intermediate shell extending about said inner shell, transversely extending members arranged between said intermediate and outer shells ing inwardly pressed portions formed in said intermediate shell and extending into contact with said imperforate portion of said inner shell to form a restricted passage connecting said resonance chamber and the space between said inner and intermediate shells.

13. A muiiler including an inner shell through which gases and sound waves pass, an outer shell and an intermediate shell extending about said inner shell, transversely extending members arranged between said intermediate and outer shells to form therewith a resonance chamber, said inner shell having a perforated portion and an imperforate portion, said intermediate shell having longitudinal inwardly extending portions thereof engaging said imperforate portion of said inner shell to form restricted channels between said extending portions connecting said resonance chamber and the space between said inner and intermediate shells and forming bottle necks to said resonance chamber.

14. In a silencer, a tubular member, another tubular member which encircles and is radially spaced from the first-specified tubular member to define with it a. chamber, and a passage through which gases and sound waves may travel extending through the inner of the tubular members, the chamber being connected to the passage as a side branch, one of the "tubular members having in it throughout a portion only of its length deformations which extend into engagement with the other of the tubular members and are separated from each other circumferentially so as to leave between them open-ended apertures which communicate at one end with the chamber.

15. In a silencer, a tubular member, another tubular member which encircles and is radially spaced from the first-specified tubular member to define with it a chamber, and a passage through which gases and sound waves may travel extending through the inner of the tubular members, the chamber being connected to the passage as a side branch, the outer of the tubular members having in it throughout a portion only of its length con-ugations which extend lengthwise of it and into engagement with the inner of the tubular members and are separated from each other circumferentially so as to leave between them open-ended apertures which communicate at one end with the chamber.

16. In a silencer, a tubular member which defines a passage through which gases and sound waves may travel, a second tubular member which encircles and is radially spaced from the firstspecified tubular member to define with it a chamber, a third tubular member which encircles and is radially spaced from the second-specified tubular member to define with it another chamber, an aperture in the first-specified tubular member which opens into the first-mentioned chamber, the second-specified tubular member having in it at one end deformations which extend into engagement with one ofthe others of the tubular members and are separated from each other circumferentially so as to leave between them open-ended apertures which communicate at one end with one and at the other end with the other of the mentioned chambers. 

